Supplementation of fexofenadine therapy with nedocromil sodium 2% ophthalmic solution to treat ocular symptoms of seasonal allergic conjunctivitis

Ragweed-induced allergic rhinoconjunctivitis: current and emerging treatment options

Ragweed (Ambrosia spp.) is an annually flowering plant whose pollen bears high allergenic potential. Ragweed-induced allergic rhinoconjunctivitis has long been seen as a major immunologic condition in Northern America with high exposure and sensitization rates in the general population. The invasive occurrence of ragweed (A. artemisiifolia) poses an increasing challenge to public health in Europe and Asia as well. Possible explanations for its worldwide spread are climate change and urbanization, as well as pollen transport over long distances by globalized traffic and winds. Due to the increasing disease burden worldwide, and to the lack of a current and comprehensive overview, this study aims to review the current and emerging treatment options for ragweed-induced rhinoconjunctivitis. Sound clinical evidence is present for the symptomatic treatment of ragweed-induced allergic rhinoconjunctivitis with oral third-generation H1-antihistamines and leukotriene antagonists. The topical application of glucocorticoids has also been efficient in randomized controlled clinical trials. Combined approaches employing multiple agents are common. The mainstay of causal treatment to date, especially in Northern America, is subcutaneous immunotherapy with the focus on the major allergen, Amb a 1. Beyond this, growing evidence from several geographical regions documents the benefit of sublingual immunotherapy. Future treatment options promise more specific symptomatic treatment and fewer side effects during causal therapy. Novel antihistamines for symptomatic treatment are aimed at the histamine H3-receptor. New adjuvants with toll-like receptor 4 activity or the application of the monoclonal anti-immunoglobulin E antibody, omalizumab, are supposed to enhance conventional immunotherapy. An approach targeting toll-like receptor 9 by synthetic cytosine phosphate–guanosine oligodeoxynucleotides promises a new treatment paradigm that aims to modulate the immune response, but it has yet to be proven in clinical trials.

Relative strength of relationships of nasal congestion and ocular symptoms with sleep, mood and productivity

BACKGROUND

Nasal congestion associated with allergic rhinitis has been shown to be the most bothersome symptom. Ocular symptoms may be troublesome to patients as well.

OBJECTIVE

To estimate the relative strength of relationships of nasal congestion and ocular symptoms associated with allergic rhinitis with patient-reported outcomes of sleep quality; practical problems; somnolence; impairment at work, class, activities; and mood.

METHODS

Patients (n = 404) presenting with symptoms of allergic rhinitis completed five patient-reported outcomes that assessed the effect of morning allergic rhinitis symptoms on patients' reports of sleep, work and activity impairment, and mood. Multiple regression analyses were used to compare the relative strength of relationships of congestion and ocular symptoms with the patient-reported outcomes.

RESULTS

The majority of patients had both nasal congestion and ocular symptoms at baseline. A single nasal congestion item and a 3-item ocular symptom score were significantly related to the patient-reported outcomes: those with more severe congestion or ocular symptoms reported more negative scores on the patient-reported outcomes. Nasal congestion had the stronger relationship with patient-reported outcomes total scores or subscales in 14 of 20 regressions.

CONCLUSION

Although nasal congestion is generally more strongly related to the patient-reported outcomes, ocular symptoms have a significant negative effect on patients' lives. Study limitations include: (1) only baseline data were used because of greater severity and variability of symptoms scores; we are unable to establish causal relationships or discuss change, only correlation/covariation; (2) recruitment took place from September through November, thus different patients might have been recruited if sampling took place during the spring; (3) patients were screened for nasal congestion not for ocular symptoms, though there was high co-occurrence of each. These limitations aside, congestion and ocular symptoms are troublesome to patients and typically co-occur. Evaluating and treating these symptoms are key to managing allergic rhinitis and improving patient-reported outcomes.

Efficacy and tolerability of newer antihistamines in the treatment of allergic conjunctivitis

Treatment for allergic conjunctivitis has markedly expanded in recent years, providing opportunities for more focused therapy, but often leaving both physicians and patients confused over the variety of options. As monotherapy, oral antihistamines are an excellent choice when attempting to control multiple early-phase, and some late-phase, allergic symptoms in the eyes, nose and pharynx. Unfortunately, despite their efficacy in relief of allergic symptoms, systemic antihistamines may result in unwanted adverse effects, such as drowsiness and dry mouth. Newer second-generation antihistamines (cetirizine, fexofenadine, loratadine and desloratadine) are preferred over older first-generation antihistamines in order to avoid the sedative and anticholinergic effects that are associated with first-generation agents. When the allergic symptom or complaint, such as ocular pruritus, is isolated, focused therapy with topical (ophthalmic) antihistamines is often efficacious and clearly superior to systemic antihistamines, either as monotherapy or in conjunction with an oral or intranasal agent. Topical antihistaminic agents not only provide faster and superior relief than systemic antihistamines, but they may also possess a longer duration of action than other classes including vasoconstrictors, pure mast cell stabilisers, NSAIDs and corticosteroids. Many antihistamines have anti-inflammatory properties as well. Some of this anti-inflammatory effect seen with 'pure' antihistamines (levocabastine and emedastine) may be directly attributed to the blocking of the histamine receptor that has been shown to downregulate intercellular adhesion molecule-1 expression and, in turn, limit chemotaxis of inflammatory cells. Some topical multiple-action histamine H(1)-receptor antagonists (olopatadine, ketotifen, azelastine and epinastine) have been shown to prevent activation of neutrophils, eosinophils and macrophages, or inhibit release of leukotrienes, platelet-activating factors and other inflammatory mediators. Topical vasoconstrictor agents provide rapid relief, especially for redness; however, the relief is often short-lived, and overuse of vasoconstrictors may lead to rebound hyperaemia and irritation. Another class of topical agents, mast cell stabilisers (sodium cromoglicate [cromolyn sodium], nedocromil and lodoxamide), may be considered; however, they generally have a much slower onset of action. The efficacy of mast cell stabilisers may be attributed to anti-inflammatory properties in addition to mast cell stabilisation. In the class of topical NSAIDs, ketorolac has been promoted for ocular itching but has been found to be inferior for relief of allergic conjunctivitis when compared with olopatadine and emedastine. Lastly, topical corticosteroids may be considered for severe seasonal ocular allergy symptoms, although long-term use should be avoided because of risks of ocular adverse effects, including glaucoma and cataract formation.